Selasa, Maret 22, 2011

Viruses in Digest system

Kuliah oleh : dr Rahmiati, FK UNLAM Banjarmasin





Virus-virus yang ditemukan di traktus gastrointestinal

Ò Rotaviruses
Ò Adenoviruses 40/41
Ò Caliciviruses
Ò Norwalk like viruses or SRSV (Small Round Structured Viruses)
Ò Astroviruses
Ò SRV (Small Round Viruses)
Ò Coronaviruses
Ò Toroviruses


Family Reoviridae
Genus Rotavirus
Other genera Orthreovirus, Coltivirus, orbivirus (sheep)

EM identification from duodenal biopsies from children with diarrhea.
"Virus particles in epithelial cells of duodenal mucosa from children with acute non-bacterial gastroenteritis," Lancet, 1:1281-3, 1973

Naked double shell capsid
11 segment double stranded RNA genome
Fecal oral transmission
Replication in cytoplasm
Fever, vomiting, diarrhea in infants and young children
Incubation period less than 48 hr, highly infectious
Infection of intestinal epithelium causes loss of electrolytes and prevents readsorption of water
Long term immunity; asymptomatic infection in adults
viral antigen detection
RotaTeq live, oral vaccine

ÒIsolated 1953 by Rowe from adenoidal tissue
ÒLinear double-stranded DNA
Ò70-75nm in diameter
ÒGenus: Mammalian AV (mastadenoviruses)
É6 human subgenera (A-F)
É51 human serotypes (1-51)
ÒKnown oncogenic potential of some serotypes
ÒCommonly used as vectors in
  gene therapy and vaccine delivery
ÒIncubation period 3 -10 days
ÒDiarrhea lasts for 10 -14 days
ÒCan also cause intussusception, mesenteric adenitis, appendicitis
ÒTreatment with cidofovir promising for severe disease in immunocompromised


Family Caliciviridae
Non-enveloped RNA viruses
with ss [+] sense RNA
27-35 nm in size
Contains single capsid protein 
Morphology typical :
32 cup-like depressions
EM appearance of “Star of David”
31-35 nm size
          E.g.- Sapporo-like viruses 

Morphology A-typical 
    •Smaller size- approx. 27 nm
Rough, feathery surface but no   internal pattern
Small Round Structured viruses
         E.g.- Norwalk-like viruses  


ÒPerson-to-person fecal-oral spread (stool/vomitus)
ÒFecal contamination of food or water
ÒFomites (stool/vomitus)
ÒIngestion of aerosolized particles


ÒSurvive on surfaces for several days
ÒSurvive in water chlorinated at routine levels (up to 10 ppm)
ÒSurvive freezing, heating up to 60°C
ÒEvidently survive in steamed shellfish

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